Street-network Sprawl in Darab, Iran

What is Street-network sprawl?

Street-network Sprawl is a way to measure urban sprawl, worldwide, through the connectedness of the streets. Less sprawl means more connected, more walkable streets. Well-connected streets – like New York City’s grid – are more walkable and can be served by public transit.

The street network is permanent, and its connectivity affects the livability and environmental footprint of cities for decades and centuries to come. In places with more connected streets, residents drive less and walk more. A well-connected street network is associated with better outcomes for health, the environment, sustainable consumption, social integration, and equity.

We can quantify how connected street networks are with the Street Network Disconnectedness Index (SNDi).

SNDi -- our measure of street-network sprawl (disconnectedness)

The SNDi is a comprehensive measurement of “sprawl”. It captures:

A higher SNDi means less-connected streets – i.e., more sprawl. For the 10137 cities in our dataset, the average SNDi is 2.25, with half of the cities' SNDis falling between 1.08 and 3.25.

More information on the sprawl index can be found in these research papers:

To see the state of street-network sprawl across the globe, visit the sprawlmap.

Darab: city in Fars, Iran

What exactly constitutes the spatial extent of the city? For these aggregations, we used the Global Human Settlement Layer Urban Center Database (GHS-UCDB) to define the boundaries of the city. These cities -- or urban centers -- cover areas that are densely populated and built-up, and so may extend beyond the spatial borders of these cities that we may be familiar with. The GHS area is shaded in blue.

View Darab, Iran on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Darab as of 2014, the overall level of street-network sprawl is 1.85, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.33, 1.69, 2.32 and 2.22. Street construction in Darab increased in disconnectivity initially but has since improved. The streets constructed in 1991-2000 were the most disconnected.

Quantity of street network construction: The street network in Darab spans a total of 190 kilometers. The period with the greatest volume of street construction was 1976-1990. These roads have an SNDi of 1.69, which is relatively well-connected.

Effect on the aggregate network: New construction in each period adds to the total stock of streets, but does not change streets that have already been built. Therefore, it has a limited effect on the street network as a whole. The SNDis of the aggregate street network in the respective time periods are 1.33, 1.56, 1.73 and 1.85. Overall, the SNDi of the aggregate street network has risen: the street network in Darab has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.22 points, but between 1991-2000 and 2001-2014, it rose by just 0.12.

Darab and Fars do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Darab peaked in 1991-2000, while the SNDi of street constructions in Fars was at its lowest in 1991-2000.

How do development practices in Darab fare in comparison to others in Fars? Most recently in 2001-2014, street construction in Darab was the 8th-most disconnected out of the 9 cities in Fars. Its position in the ranks since 1975 has risen; relative to other cities in Fars, street construction in Darab has become more disconnected. Darab ranked 9th in 1975, 6th in 1976-1990, 6th in 1991-2000 and 8th in 2001-2014.

Darab and Iran do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Darab peaked in 1991-2000, while the SNDi of street constructions in Iran was at its lowest in 1976-1990.

How do development practices in Darab fare in comparison to others in Iran? Most recently in 2001-2014, street construction in Darab was the 120th-most disconnected out of the 181 cities in Iran. Its position in the ranks since 1975 has fallen; relative to other cities in Iran, street construction in Darab has become more connected. Darab ranked 100th in 1975, 85th in 1976-1990, 87th in 1991-2000 and 120th in 2001-2014.

Darab and Fars do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Darab rose steadily, while the SNDi of street constructions in Fars was at its lowest in 1991-2000.

To date, Darab is the 8th-most disconnected out of the 9 cities in Fars. Its position in the ranks since 1975 has risen; relative to other cities in Fars, the street network in Darab has become more disconnected. Darab ranked 9th in 1975, 7th in 1976-1990, 8th in 1991-2000 and 8th in 2001-2014.

Darab and Iran do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Darab rose steadily, while the SNDi of street constructions in Iran was at its lowest in 1976-1990.

To date, Darab is the 104th-most disconnected out of the 181 cities in Iran. Its position in the ranks since 1975 has fallen; relative to other cities in Iran, the street network in Darab has become more connected. Darab ranked 100th in 1975, 99th in 1976-1990, 96th in 1991-2000 and 104th in 2001-2014.

As of 2015, Darab had a built-up area of 5.42 square kilometers, and a population of 121895 people.

These are some other cities with approximately the same population: